My four stroke engines lean out too much between full tank and empty. If I set the needle slightly rich of peak when the tank is empty and then fill the tank up, rpms are nowhere near max. The fuel tank in both planes is too low (top of tank slightly below carb).

Is it possible to fix this problem with a pump? Does the Perry oscillating pump regulate fuel flow, or does it just boost pressure? Cline regulator?

The Perry oscillating pump has worked great on my Magnum four strokes. I've used one on my .52, .61, and .91. Don't set the pressure too high because it will cause your needles to be to sensitive and may cause the mid-range to be a bit rich. If you set the pump so that your "before pump" needle settings are only slightly rich after adding the pump, then you will be just about right. Then you can adjust for close to peak without going over lean at the end of the flight.

Shiny side up!

Gary

Perry vp-20 is the vibration Pump...It is not adjustable...The Perry vp-30 ...is adjustable.


Scott

I have the vp-20 and it is adjustable. One end of the pump is the inlet nipple and the outlet side has a hex nut shape with the nipple coming out of the center. Rotate the hex in small increments to adjust the amount of flow.

Here's a link to the operating instructions for the VP-20 on the Conley/Perry Pump website:

http://www.perrypumps.com/VP-20%20and%20VP-22.pdf

Quantum Models carries this pump for about $25.

Thank You I stand corrected...LOL i didnt realize..I was lucky mine didnt need adjustment ....thanks again...

Scott

Does this mean that I can set the needle near peak with the fuel tank full, and leave the needle in that position for the entire flight?

is the perry the best pump? Isn't there another one? is it any better or any easier? :?

all i have run is the perry i do know of the cline regulator..I think they are really good products..I do know the perry is..

Scott

Dear Sandal:

The PIPE Here yet AGAIN-and still eager on those great Conley/Perry "Shaker" pumps!

I have NEVER had a fuel flow related engine stoppage with ANY four stroke engine I've ever flown with--since going with the Perry "shaker" pump when I completely converted to four stroke power in 1985-and even though I didn't fly for about 15 years, from 1986 through to 2001, those pumps were just "waiting for me" to get back into the RC hobby again...and they're still doing a great job!

The volume pumped per engine "shake" can be increased all the way up to a large 3.5 oz (99.2 cm3) of fuel per minute-enough to even feed a HUMONGOUSLY thirsty four stroke like the Saito FA-180!

I just can't say enough GOOD things about those great Perry P-20 "shaker" pumps...and the P-22 gasoline ready pumps are supposedly very nice for airshow style smoketrail fluids as well!

Yours Sincerely,

The PIPE!

sandal

You should be able to set your engine with a full tank and not go lean in flight. I always richen about 200 rpm off peak just for insurance!

Gary

Perfect. I'll order a VP-20 and prepare for a life in happiness

Hej!
Varför sätter du inte motorn lägre!?? Så slipper allt vad pumpar heter!

Hälsningar!
Jan K
Sverige

Why don't you mount the engine lower!?? Then you don't have to mess with pumps!

Don't bring more up in the air than necessary !

Regards!
Jan K
Sweden

No matter where you mount the engine, it will lean out as the fuel level in the tank drops while flying. Because of this you must set the needle richer than you may like at the beginning of the flight to be sure it doesn't lean out too much towards the end of the tank. A pump will eliminate this and the engine will run the same at the end of the tank as it does at the beginning.

John

Jan K;
I appreciate your help, but I don't understand what the !!!!s are all about. As far as I remember, I haven't done anything to offend you.

Moving the engine would help, but I'd have to make a new cowl and figure out how much up/down and left/right thrust to use with the new engine location.

JWN;
you said it. I was afraid the oscillating pump would boost pressure without any regulation (as this would give me the same problems at a higher pressure )

The nice thing about the VP-20 pump is it is self regulating. It works perfectly on it's own.

John

Dear Sandal:

The PIPE here once more-and you haven't told us yet-just WHAT size of four stroke engine are you going to use a Perry "Shaker" pump with, anyway?

As I've used these pumps with engines as small as a 6.5 cm3 OS FS-40, and as big as a 15 cm3 OS FS-90 (the OLD one with the REAR mounted camshaft) I SHOULD be able to help you determine a "baseline" or "basic" setting to help you get your pump set up, even BEFORE flying, to assure you the best chance of sucess!

PLEASE let us know just WHAT engine you're thinking of using the VP-20 "shaker" pump with-THEN I can help you get a good adjustment on the pump, "right out of the case", to help you get in the air with it, and with what should be virtually TROUBLE FREE four stroke engine operation!

Hope to hear from you soon...

Yours Sincerely,

The PIPE!

the PIPE;
I have two four stroke engines; an ASP FS30AR (GP PT-20MkII) and an OS FS-52S (Four-Star 40). The OS goes into my new plane:

I ordered a Sig Somethin' Extra yesterday. A friend of mine says he'd like one too. I might buy a GP CAP 232 or Extra 300S 40 size for myself. The important thing is that these planes - no matter which I choose - will be thrown in all directions while in the air, so a steady fuel flow is appreciated.

I haven't bought the pump yet, but as soon as I do, I will get back to you for more information about set up. Thank you!

Hej!
Ta inte illa upp ..... min avsikt var inte alls att vara ohövlig. Det är bara det att man ser så många här på R/C universe som verkar tro på en massa "gadgets" (som pumpar t.ex).
I själva verket går det alltid att få till perfekt gång på en motor om man bara följer enkla regler..... som att ha tanken placerad nära motorn, mitten på tanken ska ligga i nivå med nålröret i förgasaren, inte använda för stor tank (240cc till en 6,5-8,0cc motor t.ex) och att alltid köra sina motorer på 5-10% nitro... och inte för snålt. Följer man dessa regler kommer alltid motorerna att gå bra.
Om nu tanken sitter för högt eller för lågt ...då måste man väl göra något åt detta....och det innebär inte att skaffa en pump.....men väl att flytta motor eller tank.
Själv har jag flugit i 29 år ...tävlat i pylon segel och skalaflyg...jag deltog i pylonVM i USA -95(Muncie) och jag har lärt mig att man ska försöka göra allt så enkelt som möjligt .....Då fungerar allt oftast perfekt.
Om du flyttar motorn ...var inte orolig för att inte få samma sidoriktiing som tidigare...någon sidorikting behövs inte på de flesta modeller. Själv sidoriktar jag aldrig mina motorer, åtminstone har jag inte det på lågvingade modeller vare sig de jag har konstruerat själv eller de andra jag byggt från ritning elller byggsats.
Om du läser senaste numret av ModellflygNytt så tester jag där SIG:s CAP 231EX och där har jag monterat min MVVS 1.50 riktad rakt fram..ingen sidoriktning och ingen nedåtriktning....och den flyger väldigt bra i alla lägen.


Hälsningar!
Jan K

Yeah, what Jan said

John

Jan K;

I agree with you. But. Making a new cowl on a CAP with the engine say 2-3 cm lower would 1) be too difficult for me and 2) look incredibly silly.

The PT-20 leans out quite a bit from full to empty tank, but I don't want to mount the engine lower because of prop/ground clearance. We have a grass runway, and I run 10 and 11" diameter props.

I admit it; I am lazy. Instead of making the necessary modifications, I'm going to buy a pump. It will be like sneaking in the back door, but if the result is the same, I'd rather pay £35 than move the engine.

Hi!
Is the engine sidemounted now?

Regards!
JanK

jaka;
...I decided to rebuild my GP .20 Cub yesterday. The ASP FS30AR is side mounted in that plane. The OS FS-52S is mounted upright on the 4*40, but I am having the biggest problems with the .30 engine. The 4*40 is OK if I remember to trim the idle down towards the end of the tank.

I have a two stroke I have just put together, the fuel tank is located above the carburator and fuel leaks out just setting. I was told to put a Perry Pump regulator on the two stroke to stop this problem but it involves drilling into the crankcase. I am wanting to replace the two stroke with a four stroke. The fuel tank will still be above the carburator, will the vp-20 prevent the fuel from siphoning out when the motor is not running?

I am trying to set up a VP-20 on a .91 Saito. The pump is mounted between the motor mounts on the firewall. This pump was given to me used and works, but is out of adjustment. When I tried to run the engine, I couldn't open the high speed needle enough to make the rpm's sag. It's a real pain to get to the pump for adjustment. ( Engine has to be removed. )
If someone has a pump with the factory setting handy, and a feeler guage, I would sure appreciate the measurement from between the inside of the hex-head plug, and the edge of the boss the plug screws into. Or if someone is running one on a .91 Saito, this same dimension would sure be a help. Thanks, Tim